Interlocking system for railroads



Dec. 9, 1941. R. M. PHINNEY 2.265.247

` INTERLOCKING SYSTEM FOR RAILROADS original Filed Aug. 12, 195e s sheets-sheet 1 su ,NKB TK J @ma C (+1@ a1 @x12` I 87 8 I I IC a@ I Dec. 9, 1941. R. M. PHlNNl-:Y

INTERLOCKING SYSTEM FOR RAILROADS Original Filed Aug. l2, 1936 3 Sheets-Sheet 2 TSA . 9,- 1941. R. M.y PHINNEY y INTERLOCKING SYSTEM AFOR RAILROADS Original Filed Aug. 12, 1936 3 Sheets-Shet 3 QPS Patented Dec. 9, 1941 UNHTED STAT S PTENT @FE-ICE Robert M. Phinney, Brighton, N. Y., assigner to General Railway Signal Company, Rochester,

Application August 12, 1936, Serial N0. 95,596

Renewed September 25, 1937 li2 Claims.

This invention relates to electric interlocking systems for railroads, and more particularly pertains to an interlocking system of the entrance-exit type.

The interlocking system of the present invention contemplates a miniature track diagram located in the central control oilice which corre-- sponds to the actual track layout in the iield. Suitable initiating and completing buttons or levers are located on the miniature track diagram for the end of each route. The operation of 'an initiating button at the entrance to a route together with the contemporaneous actuation ci the completion button for the exit end of that route, compositely controls all of the individual track switches included in that route and clears the signal for such route when all of the track switches have properly responded.

One of the objects of the present invention is to provide for an interlock between the entrance and exit buttons in such a way that only one route from a. group ci conilicting routes may be established at any one time. rlhis is accomplished by means of electric circuits and relays in such a way that the number of relays required is increased the same amount for the addition of each switch and crossover in the track layout for that group, irrespective of the arrangement of the layout.

Another object of the present invention is to provide for composite route indications onthe miniature track diagram which are particularly adaptable to an entrance-exit type interlocking system.

ther objects, purposes and characteristic features of the present invention will be in part ohvious from the accompanying drawings, and in part pointed out as the description of the invention progresses.

in describing the invention in detail, reference Cil will be made to the accompanying drawings, in

which like letters in the reference characters designate similar functions or relationships with the distinctiveness between such reference characters provided by the use of distinctive preceding riumerals; in which like preceding numerals in the reference characters when applied to different letters represent the inclusion of such devices within a particular group; and in which Figs. 1 and 2 when placed side by side diagrarnmatically illustrate the control ofce and field station apparatus comprising an interlocking system of the present invention as applied to a single crossover;

Fig. 3 illustrates diagrammatically the inter- 55 lock between a plurality of switch control relays in a complicated track layout involving Crossovers and single switches; and y Fig. 4 illustrates diagrammatically a typical modied form of circuit control for the entrance and exit buttons on the control panel. l For the purpose of simplifying the illustration and facilitating in the explanation thereof, the conventional parts and circuits constituting the embodiment of the invention have been shown diagrammatically and certain conventional illustrations have been employed, the drawings having been made more with the idea of making clear the purposes and principles of the present invention together with its mode of operation, than with the idea of illustrating the specic construction and arrangement of parts that would probably be employed in practice.

The various relays and their contacts are illustrated in a conventional manner and symbols are employed to indicate connections to the terminals of batteries or other suitable sources of electric current supply instead of showing all of the-wiring connections to such terminals.

The symbols (-l) and are employed to indicate the positive and negative terminals respectively of suitable batteries or other sources of electric energy; and those terminals with which these symbols are used are presumed'. to have current flowing from the positive terminal designated (-i) to the negative terminal designated The symbols employed with any one circuit are considered to designate the terminals of the same battery or other suitable source, but it is to be understood that as many separate sources may be provided as found necessary, or as many sources may be combined into a single source as found expedient inthe practice of the invention. If alternating current is employed, then the symbols should be considered to represent the instantaneous relative `polarities of the respective terminals.

Where groups of devices are referred to in a general way, such devices will be designated by the letters or preceding numerals characteristic of such groups instead of mentioning each specific reference character of that group of devices,

ArPARATUs Track layout-In Fig. 2 of the accompanying drawings, the invention has been shown applied to a track layout including a stretch of double track connected by a crossover having switch points TSA and TSB. The stretch of double track includes a main line extending from a signal 3 to a signal 4, and another main line extending from a signal 5 to a signal 5. Signals 3 and 6 govern the traic over the crossover as well as over the main line tracks with which they are associated.

Inasm-uch as the opposite ends of a crossover are usually operated at the same time, the crossover may be considered as operated by a single switch machine SM, which may be of any suitable type, such for example, as disclosed in the patent to W. K. Howe, Patent No. 1,466,903,

dated September 4, 1923. However., two switch machines SM may be employed, if desired, all within the scope of the present invention.

It should also be understood that the nvention is not limited, as thus shown, to the control of a crossover and signals of this chosen layout, but may be extended for any desired number of switches and signals and may be readily ap-plied -f to allV types of'track layouts `found in interlocking plants, and 'when thus vappliedto more Vcomplicated track layouts reference should be made to Fig. 3 which illustrates the kmanner in which the features of the present invention illustrated in Figs. 1 and 2 should be `applied to a complex track layout. The manner in which the present invention applies to a single track switch instead of a crossover, will be pointed out hereinafter. by mentioning those parts of the present disclosure which may be readily `omitted when yonly a single turnout switch is controlled by la system constructed in accordance with the present invention.

The 'signals 3, '4, 5 and 6 are assumed to be color light signals giving the usual indications of green for clear and red for danger or stop, and yellow, if an ladded Aindication is desired, for caution. However, these signals may be of `the search light type, vthe semaphore type, or any f othersuitable `type instead of the particular type chosen for the embodiment of the present invention.

The track layout has been shown as divided into two track circuits 8 and 9 by insulated joints, which track circuits are provided with the usual track batteries and track relays of which track relays 8T and 9T have been shown. These normally energized Vtrack circuits are Wired in the usual manner to provide for fouling protection and to provide for the insulation of the track switches, such details of wiring having been omitted for the sake of simplicity in the disclosure.

The crossover, including the track switches TSA and TSB, is shown as having a 'single switch position repeating relay WP of the usual polar neutral type. This relay WP is energized with one polarity or the other in accordance with the normal and reverse locked positions of the track switches TSA and TSB with the switch machine SM in corresponding positions, and is deenergized Whenever the track switches are unlocked or. are in operation. The polarized circuit for controlling such a switch position repeating relay is governed through the medium of a point detector contact mechanism such as shown for example in the patent to C. S. Bushnell, Patent No. 1,517,236, dated November 25, 1924, it being understood that there would of course be two such mechanisms when two switch machines SM are employed.

Control machina-A suitable control machine is located in the central oice and is provided with a control panel on which a track diagram is constructed corresponding to the actual track layout in the leld. The construction of this track diagram is such that the trackway is made up of molded glass sections, or other suitable transparent material, which form the trackway. These sections are distinctively colored for the different facts which their illumination are assigned to indicate.

More specically, the sections STK and STK "1 which take locations on the diagram corresponding to the points of the switches TSA and TSB, are preferably of amber color so that when their respective indicator lamps 8TK1 and 9TK1 are illuminated, a distinctive indication of track occupancy is indicated to the operator. The sections NKA, RK and NKB are preferably red in color so that when their respective indicator `lamps 'NKA1, RK1 and NKB1 are illuminated, an indication is given to the operator which is distinctive from the other conditions of illumination on the panel. These indicator sections NKA, RK and NKB represent the routes set up, when `illuminated, and are unilluminated so long as such routes are free to be included in newly proposed routes. The particular signicance of these indicators as cleared route 'designators to warn the operator against endeavoring to set up conflicting routes will be more readily 'apparent in the description of the operation of the system.

Between certain illuminated trackway sections on the 'diagram and at route determining points represented in the 'track layout, are suitable entrance and exit buttons Awhich control the setting up of routes andthe clearing of the signals for such routes. An entrance button NB is provided for each of the signal locations, such as entrance buttons 3NB, 4NB, v'dNB and BNB for the respective signals 3, 4, 5 and 6. An exit Ibutton XB is provided for the end of each route, shown specifically as exit buttons BXB, 4XB, SXB and 6KB. It is to be understood, that the ends of the routes may or may not correspond to the locations of the exit buttons on the miniature track diagram, as a route is usually considered to extend from one particular signal to the next signal governing traflic in the same direction or to some arbitrarily chosen point.

Each entrance button NB is in the form of a knob which is rotatable 90 from a normal position to an operated position. The 90 rotation of a button NB, such as button SNB, in a clockwise direction closes its associated contacts, and remains in that position Vto keep its contacts closed until it is manually restored to its normal position. For the purpose of conserving space on the control panel, the exit buttons XB are located within the entrance buttons NB. These exit buttons XB are of the self-restoring push button type, and to further conserve space have within their centers, the signal indicators SK which, when illuminated, indicate the cleared condition of their` corresponding signals. Thus, the indicators SSK, 48K, SSK and BSK are provided to indicate the clear condition of their respective signals 3, 4, 5 and 6, all of which is accomplished through means not shown in the present disclosure for the sake of simplicity, although reference may be made to the application of S. N. Wight, Ser. No. 69,905, iiled March 2l), 1936, for the details of such control. It should also be noted, that the construction of the entrance-exit and signal indicator combination NB-XB-SK has been shown in Fig. 10 of the above mentioned application of S. N. Wight, Ser.

No. 69,905. The signal indicators SK are preferably green in color when illuminated.

Although it is preferably desirable that the trackway indicators TK, RK and NK give a dark board appearance, when unilluminated, it is also desirable that these indicator sections and intervening marked (or dummy) sections on the panel, clearly indicate the track layout even while all of the indicators are unilluminated, yet at the same time provide distinctiveness between the different kinds of indicators. The route indicator sections are provided with dark spots for the insulated joints or ends of the track circuits, which has been more particularly illustrated for the indicator RK. It is of course apparent that the insulated joints do not need to be illustrated when they fall opposite a signal location involving an entrance and/or exit button on the control panel.

An emergency switch control lever SML is also provided to control the operation of the switch machine SM under certain emergency conditions hereinafter pointed out in detail. This emergency switch control lever may be suitably located upon the control panel, but is preferably located on the back of the control machine, because of the fact that such lever is only used for emergency conditions. Associated with the lever SML is an indicator lamp COR, which is illuminated Whenever the crossover, including switches TSA and TSB, is in mid-stroke or is out of correspondence with its switch machine control as set up either by the composite entrance-exit route control or by the emergency switch control lever SML.

System apparatus-The entrance buttons NB and exit buttons XB are respectively shown as connected to the contacts which they operate by dotted lines so as to make their relationships readily apparent. Associated with each entrance button NB is an entrance relay NR; and Simi l larly associated with each eXit button XB is an exit relay XR. The entrance relay NR and the exit relay XR for each signal location are interlocked as will be described hereinafter.

The entrance relay NR for one end of a route and the exit relay XR for the opposite end of that route jointly control the positioning of the proper switch control relays for the switches in that route. For the crossover of Fig. 2, switch relays WNA, WR and WNB are provided to be thus controlled by the entrance and exit relays NR and XR, which neutral switch controlling relays in turn govern the operation of the switch machine SM through the two position polarized relay WZ. Associated with the control for each switch machine is a lock relay L which prevents the operation of the switch machine SM when itis unsafe for the track switches TSA and TSB to be operated.

Relays NCR and RCR are provided to indicate when the track switches TSA and TSB are in correspondence with their control as will be pointed out hereinafter.

A signal control relay G is provided for each signal for causing that signal to indicate clear or stop. These signal relays include relays 3G, 4G, 5G and 6G for their respective signals 3, 4, 5 and E, and are selectively controlled in accordance with the position and locked condition of the track switch and in accordance with the condition of the entrance rand exit relays NR and XR., as will be hereinafter described.

A signals at stop relay M is energized when all of the signals 3, 4,' 5 and 6 are at stop, and is deenergized whenever any one of these signals is at clear.

In an interlocking system, there is usually suitable approach locking and route locking means associated with the signals and switch control means, and the system of the present invention is contemplated as having applied thereto any suitable approach and route locking means as desired in accordance with the practical operation of trains for any particular installation, but for the purpose of illustration, directional stick relays BES, GWS, EES and SWS are associated with their respective track circuits 8 and 9, as indicated by their preceding numerals, to provide what is termed rear release route locking, all of which has been disclosed in the prior application of C. F. Stoltz, Ser. No. 402,527, led October 25, 1929, to which reference may be made for the details of control for such relays.

It is considered sufficient for an understanding of the present invention to know that the relay tBES is deenergized when the signal 3 is cleared and is maintained deenergized, although the signal is returned to stop, so long as a train is on the track circuit 3, but during such deenergized condition of the relay SES, the relay RWS remains picked up. Similarly, the relay SWS is deenergized when the signal d is cleared and remains deenergized so long as a train is on the track circuit 8, although the signal 4 is returned to stop, but during such deenergized condition of the relay SWS, the relay SES remains picked up.

Likewise, the relay QES is deenergized whenever the signal 5 is cleared and is maintained deenergized, although the signal is returned to stop, so long as a train is on the track circuit 9, but during such deenergized condition of the relay SES, the relay SWS remains picked up. Similarly, the relay SWS is deenergized whenever the signal 6 is cleared and remains deenergized so long as a train is on the track circuit 9, although the signal 6 is restored to stop, but during such deenergized condition of the relay SWS, the relay SES remains picked up.

It is also noted in this connection, that when the track switches TSA and TSB are in reverse positions to allow traflic to pass over the crossover and the signal 3 is cleared, both the relays SES and SES are deenergized; and similarly, when the signal 6 is cleared for traic in an opposite direction over the crossover, both the relays SWS and SWS are deenergized.

It is believed that the remaining features of the present invention will best be understood by considering the detailed operation of the system.

Normal lconditions. Although the track switches TSA and TSB are usually left in their last operated positions under normal operating conditions, they have been shown in positions for the passage of main line trafc. The signals are considered to be normally at stop with the lower or red indicator of each signal normally illuminated, unless approach lighting features are employed in accordance with the usual practices.

With the track sections 8 and 9 unoccupied, the respective track relays 8T and ST are of course normally picked up.

The lock relay L, the directional stick relays 8ES, SWS, SES and SWS, the signals at stop relay M, and the relay WP, are normally energized, but the circuits and various conditions governing these relays will be discussed in detail hereinafter.

VAll of the indicators on the control panel are normally deenergized to provide what has been conveniently termed a normally dark board. Y Entrance-emit Toute interlock-When the operator desires to set up a route from the signal 3 to the signal 4, for example, he rotates the entrance button 3NB in a clockwise direction to its operated position which closes a circuit for the entrance relay 3NR from (-1-), through a circuit including closed lever contact l5, back contact I6 of 'exit relay BXR, winding of relay 3NR, to This energizing circuit for the entrance relay 3NR remains closed so long as the entrance button SNB is left in its operated position. The picking up of the contacts of the entrance relay 3NR also prevents the operation of its associated exit relay 3XR by disconnecting at back contactl I1 from the right hand terminal of relay 3XR.

After actuating the Ientrance button SNB, the operator then glances along the miniature trackway and finds that there are no indicators illum'inated between such entrance button 3NB and the exit button 4XB which designates the end of the route which he desires to set up. The operator then actuates the exit button 4XB which closes a pick up circuit for the exit relay 4XR from (-1-) through a circuit including back contact I8 of exit button 4XB, winding of exit relay 4KB., back contact I9 of entrance relay 4NR, to

The condition-s under which the illumination of an indicator in the trackway advises the operator against the establishment of a route will be discussed in detail after a description of the specific control for the various indicators has been given.

The contemporaneous operation of the entrance relay 3NR and the exit relay 4XR closes an energizing circuit for the switch control relay WNA from (-1), through a circuit including front contact 2B of relay 3NR, lower winding of relay WNA, back contact 2l of relay WR, back contact 22 of relay 4NR, front Contact 23 of relay 4XR, to The current which flow-s in this circuit causes the relay WNA to pick up its contacts, and to remain picked up so long as this circuit is closed.

` When the relay WNA responds, a stick circuit is closed for the relay 4XR- from (-1), through a circuit including front contact 24 of relay SNR, front contact 25 lof relay WNA, back contact 26 vof relay 4NR, front Acontact 2l of relay AXR, windings of relay 4XR, back contact I9 of relay 4NR, to

As soon as this stick circuit is closed, the operator may then release the exit button 4XB and the exit relay 4XR remains picked up dependent uponthe restoration of the entrance button 3NB. The operator is advised as to the time at which he may release the exit button 4KB by the illumination of the route indicator section NKA, because this indicator section becomes illuminated immediately upon the picking up of the relay WNA. The lamp NKA1 is energized by a circuit closed from (-1-), through a circuit including front contact 28 of relay WNA., bus wire 13, indicator lamp NKA, to

It will be obvious that the opening of back contact It!) of relay 4KB will prevent the accidental energization of relay 4NR. Also, the picking up of the contacts of the relay WNA prevents a conflicting route from being established by reason of the opening of back contacts 29 and 30, which feature will be described in detail hereinafter.

The picking up of the contacts of the relay WNA effects the control of the switch machine by energizing the relay WZ to a normal position by a circuit closed from (-1-) through a circuit including front contact 3| of relay L, front Contact 32 of relay 9T, front contact 33 of relay 8T, wire 34, front contact 35 of relay l/VNA, wire 33, lower winding of relay WZ, to The current which flows in this circuit actuates the polar contacts of relay WZ to the right hand normal positions in which energy is supplied to the switch machine SM by a circuit closed from (-1-), through a circuit including front contact 31 of relay 6T, front contact 38 of relay 9T, front contact 39 of relay L, polar contact 40 of relay WZ in a right hand position, through the switch machine SM, to The yswitch machine SM, thus energized, causes the operation of the track switch-'es TSA and TSB to normal positions which is repeated by the relay WP. When the relay WP assumes a normal energized position, the normal correspondence relay NCR is energized by a circuit closed from (1-), through a circuit including iront contact 4l of relay WNA, wire @2, windings of relay NCR, back contact 43 of relay RCR, polar Contact 44 of relay WP in a right hand position, front contact 45 of relay WP, to

While all of the switch control relays WNA. WR and WNB for this switch machine SM are deenergized, a pick up circuit is closed for the relay L from (-1-), through a circuit including back Contact li! of relay WNA, back contact 45 of relay WR, back contact 41 of relay WNB, wire 48, back contact 49 of relay NCR, back contact 50 of relay RCR, front contact 5l of relay 8T, front contact 52 oi relay 9T, front contact 53 of relay BES, front contact 54 of relay SWS, front contact 55 of relay SES, front contact 56 of relay SWS, front contact 51 of relay M, windings of relay L, to

Upon the picking up ofthe relay WNA, this pick up circuit just traced for the relay L is broken at back contact 4 I but the relay L remains picked up by reason of its stick circuit which is closed from (-1-), through a circuit including front contact 53 which applies energy to the heel of contact 49 and thence through the remainder of the pick up circuit for the relay L.

Thus, upon the picking up `of the relay NCR, and the opening of its back contact 49, which is included in both the pick up and stick circuits for the relay L, the relay L is caused to drop away. If the crossover TS is required to be operated, then the relay L does not drop away until the crossover reaches a position in correspondence with the switch control relays WNA, WR or WNB. But, if the crossover TS is already in the position required for the route to be established, then the picking up of the correspondence relay for that route occurs immediately following the picking up of a switch control relay and the relay L immediately drops away.

In the particular case under consideration, the relay NCR picks up back contact 49 and the relay L drops away, so that open front contact 3l prevents further control of the relay WZ and so that open front contact 33 removes all energy from the switch machine SM.

When the lock relay L drops away, indicating the completing of the route so far as the position of the track switch TSA is concerned, a circuit is closed for energizing the signal 3G from (-1-), through a circuit including front contact 59 of relay GXR, wire 80, back contact 6l of relay L, front contact 62 of relay NCR, wire 63. back contact 64 of relay 3XB., front contact 65 of relay SNR, wire 66, windings of relay 3G, to

The picking up of the relay 3G changes the indication of the signal 3 from stop to clear allowing the passage of a train over the track- Way.

The relay M is deenergized by reason of the opening of back contact 61 of relay 3G, which relay M is normally energized by a circuit closed from (-1-), through a circuit including back contact 61 of relay 3G, back contact 68 of relay 4G, back contact 69 of relay 6G, back contact 1i) of relay 5G, windings of relay M, to

The deenergization of the relay M further opens the pick up and stick circuits of lock relay L at open front contact 51. The energization of the signal relay 3G also effects the deenergization of the route locking relay 8ES which further opens the pick up and stick circuits for the lock relay L at front contact 53.

The closure of back contact 1i of relay SES closes another energizing circuit for the normal route indicator lamp NKAl from through a circuit including back contact 1I of relay BES, polar contact 12 of relay WP in a right hand position, bus wire 13, indicator lamp NKA1, to

Let us assume that the train accepts the signal 3 and passes over the track circuit 8. The occupied condition of the track circuit 8 deenergizes the track relay 8T which through back contact 31 also supplies (-1-) energy to the wire 13 for energizing the indicator lamp NKAl, and which through back contact 1li supplies energy from (-1-) to the wire 15 for energizing the track indicator lamp STKl. This illuminates the track indicator section STK advising the operator that the train has accepted the route.

Ii the signals are made semi-automatic, then the occupied condition of the route will cause the signal 3 to go to stop unilluminating the signal indicator SSK, but irrespective of whether the signal 3 is put to stop automatically by the presence of a train or by manual manipulation of the entrance button 3NB to a normal position, the route indicator NKA remains illuminated so long as the train is on the track circuit 8. This is because the back contact 31 supplies energy to the wire 13 through polar contact 12 of the relay WP, although the front contact 23 of the relay WNA may be open. In other words, the occupied condition of a track circuit subsequent to the clearing of a route in which such track circuit is included, causes its corresponding route section indicator to continue to be illuminated, as well as to cause the contemporaneous illumination of the associated track indicator, such as indicator BTKI. If the route includes a large number of track sections, then there is a directional stick relay, such as relay 8ES, for each of the track sections, which directional stick relays for those track sections in advance of the track section on which the train is located, are held` deenergized by the presence of the train in the route although the governing signal is returned to stop. Thus, the respective route indicators, such as NKA for example, are maintained illuminated in advance of the train by reason of the back contacts of the directional stick relays such as Contact 1| of the relay BES, for example.

In other words, for a large or complicated track layout, where there are a plurality of track circuits in a route, each track circuit is provided with its directional stick relay which when held deenergized by a train passing through the route, maintains its respective route indicator illuminated. But, as the train passes through the route, the route indicators for the track sections in the rear of the train become successively unillurninated. rihe track indicators TK are illuminated only When their respective sections are occupied by a train.

Interlock against conflicting muta- Let us assume that the route from signal 3 to the signal i has been set up, as above described, that the entrance button 'NB is in an operated position holding the relays SNR, fiXR and WNA picked up, and that the operator unadvisedly proposes to set up a conicting route from signal 6 to the signal 3.

Under such conditions, the operator rotates the entrance button GNB in a counter-clockwise direction to an operated position. He then operates the exit button 3X8 disregarding the illumination or' the normal route lockdarnp for that crossover NKA. The actuation of the entrance button GNB closes a pick up circuit for the relay (SNR from (-1-), through a circuit including contact 89 of entrance button SNB, back contact 8l lof relay SXR, windings of relay GNR, to

The actuation of the exit button SKB accomplishes no useful purpose because the closure of back Contact 82 of this exit button cannot energize the relay 3XB. because of the open back contact I1 of the relay SNR. It will be noted that the front contact 2S supplies positive potential (-1-) to the left hand terminal of the relay WNA and would also supply such energy to the left hand terminal of 4the relay WR, but this is prevented with the relay WNA picked up opening back contact 3i). Therefore, the establishment of a conflicting route is effectively prevented.

Electric Zoclc equivalent- Let us now assume that the operator has restored to stop the route from the signal 3 to the signal 4 by returning the entrance button SNB to a normal position, but

that the train which accepted the clear signal 3 is l still on the track section 8 (or sorne other track section included within the route when a more complicated track layout is involved), so that the lock relay L is maintained deenergized. Then assume that the operator successively actuates the entrance button BNB and the exit button 3XB. The relay (SNR is picked up. The relay 3XR is picked up by a circuit closed from (-1-), through a circuit including back Contact 82 of the exit button SXB, windings of relay 1XR, back contact I1 of relay 3NR, to

When the relay SXR picks up a circuit is closed for the relay WR, from (-1-), through a circuit including front contact 813 of relay SKR, back contact 2li of relay SNR, back contact 3i of relay WNA, lower winding of relay WR, back Contact g5 of relay WNB, front contact 83 or relay BNR,

The closure of front contact 85 of relay WR completes a stick circuit for the relay 3XB. from (-1-), through a circuit including front contact 81 of relay ENR, back contact 88 of relay WNB, front Contact 8E of relay WR, back contact 25 of relay WNA, back contact 24 of relay SNR., front contact S9 of relay 3XR, windings of relay SXR, back contact I1 of relay SNR, to Thus, the relays 3A u and WR are maintained energized until the entrance button SNB is restored to a normal position.

The closure of front contact 46 of the relay cannot energize the relay RCR because the 'polar contact l44 ofstherelayV WP is in a normal position; while the closure cf front contact 99 of thev relay WRcannot energize the relay WZ because the lock relay Lis dropped awaydue to 'the occupied condition of the track circuit 8 (or some other track circuit in the route holding the -associated route stick relays deenergized, which in turn hold relay L deenergized).

Even if the train in such route from signal 3 to signal 4 passes out of the route allowing the track relays and directional stick relays for that route to be picked up, the switch controlling relay WZ will not be energized upon such departure as the lock relay L cannot be picked up until all' of the switch controlling relays WNA, WR and WNB are dropped away while the track switches TSA and TSB may be safely operated.

In other words, it is necessary for the opera- 4tor to return the entrance button SNB -to its normal position dropping away the relays BNR, SXR and WR and again actuating the entrance button SNB and the exit button SXB to pick up the relays, as above described. While the relay WRA is thus deenergized, the pick up circuit for the-Q5 lock relay L is closed for a sufcient time through the back contacts 4|, 46 and 4l' of the relays WNA, WR, and WNB to pick up relay vL and renderv it dependen-t upon its stick circuit so that upon the subsequent picking up of the relayWR," the front contact 90 closes a reverse energizing circuit for the switch controlling relay WZ from through a circuit including front contact 'of relay ENR, wire |69, windings of relay 6G,

to Y

The energization of the relay GG changes the indication of the signal 6 from stop to clear for the passage of a train over the crossover, in a similar manner as described for the route from signal 3 to signal 4.

This route may be put to stop as soon as the train enters such route either automatically or by the manual manipulation of the entrance button SNB to its normal stop position. Even though the signal 6 may be automatically put to stop, the entrance button @NB must be manually restored.

It may be well to note Ahere that during every operation of the track switches TSA and TSB, orany time that they are out of correspondence with their control set up in relays WNA, WR and WNB, the correspondence lamp COR is illuminated. For example, with either or -both of the relays WNA and WNB picked up, potential is supplied to the wire 42 in an obvious manner so that with polar contact il in a reverse position, the correspondence lamp COR is energized over wire |62. Similarly, whenever the relays WR is picked up, energy is supplied to the wire 92 so that with the polar contact lili of relay WP in a right hand position the correspondence lamp COR is energized over the wire |92.

As soon as the reverse relay WR responds to its entrance-exit control, as above explained, the

reverse indicator RK is illuminated by reason of the energization of its indicating lamp RKl 3| of the relay L, front contact 32 of relay 9T,

front contact 33 of relay 8T, wire 34, front con-- tact 90 of relay WR, wire 9|, upper winding of the relay WZ, to As :the upper and lower windings of the relay WZ are differentially connected, the current which flows in this circuitr through the upper winding of the relay WZ- causes the actuation of its polar contacts to left hand position. The reverse operating circuit for the switch machine SM is now closed from through a circuit including front contact 31 of" relay BT, front contact 38 of relay 9T, front contact 39 of relay L, polar contact 49 in a left hand position, through the switch machine SM, to During this reverse operation of the switch machine SM, Ithe relays NCR and RCR are bothy deenergized, so that the lock relay L is maintained energized through its stick circuit including back contacts 49 and 59.

As soon as the track switches TSA and TSB are operated to their reverse locked positions by the4 switch machine SM, which is repeated by the relay WP, an energizing circuit is closed for the reverse correspondence relay RCR, from. (-1-), through a circuit including back contact 4| of relay WNA, front contact 46 of relay WR, wire 92, back contact 93 of relay NCR, windings of relay RCR, polar contact 44 of relay WP in a left hand position, front contact 45 of relay WP, to

This picking up of the relay RCR and opening of back contact 50 deenergizes the lock relay L, thereby eiectively preventing further operation of the switch control relay WZ and the switch machine SM at contacts 3| and 39. The drop away of relay L also closes the signal clearing circuit for the signal relay 6G from through a circuit including front contact 64 of relay SXR, wire 63, back contact 62 of relay NCR, front contact 94 of relay RCR, back contact 95 of relay NCR, back contact 96 of relay L, wire 92', back contact 98 of relay BXR, front contact 99 through frontv contact |83 over the bus Wire |94, and is maintained energized so long as the train is on either or both of the track sections 8 and 9 by reason of the supply of energy from (-1-) through back contact |95 of track relay 9T, polar contact |06 in a left hand position to the bus wire |94, and also by reason of the supply of energy from through the back contact 31 of relay 8T, polar contact 12 in a left hand position to the bus wire |44. Also, the contacts |91 and |98 of the relays SWS and QWS are elective so long as the crossover is in advance of the train in the route to 'supply energy through polar contacts l2 and I respectively left hand positions to the wire |04 for the lamp RK1.

The occupied condition of the track circuit 9 closes back contact |99 of track relay 9T and energizes the indicator STKl over the wire H0 to illuminate the track section indicator 9TK.

Establishing a parallel route.-Assuming that the route from the signal 3 to the signal 4 has 5 been set up, as above described, any number of parallel or non-conflicting routes can be established, as for example, the establishment of a route from the signal 5 to the signal 6. To do this, the operator actuates the entrance button 5NB to an operated position which closes a circuit for the entrance relay 5NR from through a circuit including contact l I in an operated position, back contact ||2 of relay SXR, windings of relay ENR, to The operator then actuates the exit button @XB which closes a pick up circuit for relay SXR from through a circuit including back contact ||3 of vexit button 6KB, windings of relayY XR, back contact |'4 of relay SNR, to

The contemporaneous energization of the relays 5NR and GXR closes an energizing circuit for the relay WNB from through a circuit including front contact I|5 of relay 5NR, back contact H6 o relay WR, lower winding of relay WNB, back Contact 83 of relay SNR, front contact III of relay SXR, to

The energization of the relay WNB closes front contact 41 to energize the relay NCR. and closes front contact H8 to energize relay WZ, but havthe relay'WNA, as the contacts 35 and Ii are in multiple.

Irrespective of whether or not there is a route set up from the signal 3 to the signal il, front contact II9 of relay WNB energizes the lamp NKB1 over bus wire I 2E) to illuminate the route locking section NKB. This section will be maintained illuminated by reason of the control of lamp NKBl in a similar manner as explained for NKAl. In other words, the contact ISS of the track relay ST energizes this indicator lamp N'KB1 through polar contact I in a right hand position over wire I2@ so long as the track circuit 9 is occupied. Similarly, the relay QES representing the directional route stick locking for the route, controls through its contact iZI the ener-' gization of the lamp NKB1 with polar contact IE5 in a right hand position the same as the relay BES controls the indicator lamp NKAl.

However, we assumed that a route was established between the signals 3 and fl, which means that the relay NCR is picked up and the lock relay L is dropped away. Therefore, immediately upon the energization of both of the relays NR and SXR, a circuit is closed for the relay G from (-I-), through a circuit including front' contact 93 of relay iSXR, wire back contact Q55 of relay L, front contact :l5 of relay NCR, wire I4I, back contact |52 of relay 5KB., front contact M3 of relay ENR, wire Mtl, windings of relay 5G, to

The picking up of the contacts of the relay 5G causes the signal 5 to change its indication from stop to clear, and also deenergizes the relay M at open back contact 1) for further holding the lock relay L deenergized, as previously described. l

This route may be put to stop in the same manner as described for the other routes, namely, by returning the entrance button 5NB to its normal position.

Emergency switch control-The individual manual control of track switches in an interlocking plant is desirable under certain emergency conditions which may arise such as the operation of a track switch back and forth when it fails to entirely complete an operating stroke by reason of ice, lumps of coal, or the like. Also, it is sometimes necessary to mechanically set up a route through the track layout for the passage of hand cars and the like, although it is not desired to clear a signal for such a route. It is also sometimes desirable to provide means whereby the operator can manually determine which of two routes shall be superior in a group of optional routes, although the system under normal operation automatically determines this superiority between such optional routes. This will be discussed more in detail in connection with the more complicated track layout shown in Fig. 3, merely the details of the individual manual control being discussed at this point.

This individual manual control is provided in accordance with the present invention so as to be possible so long as the track switch may actually be operated, but when it is under the control of the entrance-exit relays, or is locked by reason of the presence of a train, such individual manual control is prevented.

More specifically, the operation of the lever SML from a central position to a normal operating `position energizes both of the relays WNA and WNB, but the operation of lever SML from a central position to a reverse operating position energizes the reverse relay WR.. This is accomplished by supplying energy for the upper winding of relay WNA through contact E30 in an upper normal operating position and through back contact ISI of relay WR. and at the same time supplying energy through contact I32 in an upper normal operating position to the upper winding of relay WNB and through the back contact ISI of relay WR. Likewise, with contact |39 in a lower reverse operating position, the upper winding of relay WR isv energized through back contacts 29 and I33 of relays WNA and WNB respectively.

It will thus be apparent, that if either or both ci the relays WNA or WNB are energized by reason of the entrance-exit control, then relay WR cannot be energized by the manual lever SMIL because of open contacts 29 and/or I33. On the other hand, if the entrance-exit control causes the energization of the relay WR, the lever SML cannot cause the energization of either of the relays WNA or WNB because of the open back contact I3I. The converse is also true, namely, the individual manual energization of relays WNA and WNB prevents the entranceexit control of WR, while the individual manual energization of relay WR prevents the entranceexit control of WNA and WNB.

The relays WNA and WNB, when manually picked up, cause the normal operation of the switch machine by controlling the relay WZ, as previously described; and similarly, the manual picking up of the relay WR. causes the reverse operation of the switch machine through the relay WZ, as previously described. This of course assumes that the track switches TSA and TSB can be safely operated by reason of the energized condition of the lock relay L.

The reason that both of the reiays WNA and WNB are picked up by the lever SML, is so that both of the route indicator sections NKA and NKB will be illuminated when the crossover is under individual manual control. So far as the actual control of the operation of the crossover is concerned, it could be accomplished by a single one of these relays, as will be readily apparent.

Operation of a single track switch-It will be readily appreciated that a single track switch requires only two switch control relays, such as relays WNA and WR, although three relays are required for a crossover for the purpose of the entrance-exit control and indication. In other words, for a single track switch, the relay WNB and its contacts can be readily eliminated. In place of the contact on the relay WNB, the circuits would be carried directly to the relay WR and the other circuits would likewise be modified in accordance with the particular track layout and conditions involved in the remaining portions of the system. Similarly, the contact I32 on the lever SML and its circuit can be eliminated. The back contact |33 will be elimiriated'with negative potential directly applied to the right hand terminal of the relay WR.

It will be readily apparent that the contacts 41, I i8 and ll i9 will be unnecessary, also that the stick circuits for the entrance and exit relays vwill be selected on the basis of a single track switch instead of a crossover with the contact 88 omitted. If the switch TSA were a single switch andfdid not have the opposite end TSB to form a crossover, there would be no signal 5 and its associated controls so that relay 5NR and SXR w-ill be veliminated and the circuit from front contact 86 of relay WR will be carried directly to the heel of contact 81 of relay BNR. Further description along this line appears unnecessary, as the usual principles of circuit work may be used in this connection, enough having already been said to furnish a disclosure for the basis of claims insofar as the present invention is involved in this modification of the disclosure. y

-M odifzcation of Fig. 4.-Fig. 4 illustrates a modi-fication of the entrance-exit control more spe- 'ciiically applied to the signal 3 as indicated by its Vreference characters, but this arrangement should be considered as applied to each yof the entrance-exit buttons. This form shows how the invention may be practiced without the entrance relays NR by using additional contacts on the 'entrance 4buttons NB for the various circuit selections involved.

With reference to Fig. 4, it is apparent that the exit button 3X3 has the contact 82 associated therewith, and similarly, the entrance button ENB has the contact i5 associated therewith, the same as in Fig. 1. But an added contact itl is provided to take the place of contact 20, while a contact 53 is provided to take the place of contact'.

When the entrance button BNB is rotated to an operated position, energy is supplied to the control circuit for the associated switch control relays from (-l-), through contact itl in an operated position, back contact |52 of exit relay SXR, to the circuit selections as shown in Fig. 1, or as shown in Fig. 3 causing the operation of the switch controlrrelays jointly with the operation of the eXit relay XR at the opposite end of the self-selecting network.

f With the entrance button BNB in an operated position and the proper selections having been made by the switch control relays, then the signal circuit is completed through a contact 53 of the entrance button 3NB in a similar manner as described in Fig. l with regard to contact 65 on relay 3NR.

With the entrance button SNB in an operated position, it is readily apparent that the closure of contact 32 oi exit button 3X3 cannot energize the relay SXR because at such time energy is supplied through contact i5 in an operated position and back contact i5@ to the stick circuit selection for the exit relay XR at the opposite end of the particular route selected.

Assuming the entrance button SNB to be in a normal position, the actuation of the eXit button 65 SXB closes a circuit for lthe relay SXR from (-17) through a circuit including contact i5 in a nor-V mal position, back contact 82 of exit butt-on 3X3, windings of relay BXR, to (-7). When the selfselecting network has set up the proper circuit selections for the exit relay stick circuit, such stick circuit cr'relay BXR includes front contact |50 in a manner which is entirely analogous to the description with regard to Fig. l.

This arrangement provides the vsame interlock-75 as provided in Fig. l, that is, the operation of the entrance button SNB cannot interrupt the control for the exit relay SXR when it is energized, nor can the operation of the exit button BXB in` terrupt or change the control provided by the entrance button BNB when such button is in an operated position.

Track layout of Fig. 3.-A track layout has been illustrated in Fig. 3 as including a stretch of double track between signals Il-l2 and signals I3-l4 with two turnout tracks including switches IGTS and HSTS, as well as entering signals li! and I5. Two crossovers are provided, one including the track switches I'lTSA and NTSB, and the other including the track switches IBTSA and lSTSB.

Associated in the central office with each of the signal locations are the entrance and exit buttons and each of the indicatorsas described in connection with Fig. 1. In other words, the track layout is provided in miniature on the control panel the same as described for Fig. 1 but arranged for the complicated track layout herein shown. The entrance and exit buttons have not been shown, but the entrance and exit relays NR and XR, which are controlled thereby, have been shown in block form and given reference characters with preceding numerals to designate the particular signal locations with which they are associated. As these entrance and exit relays are connected as typically taught in Fig. l, it is believed that further details in this connection are unnecessary in View of the detailed description given for such operation and control in connection with Fig. 1.

Each of the Crossovers is provided with switch control relays WNA, WR and WNB, shown specically as relays I'IWNA, lWR and I'I'WNB for the crossover including track switches I'TSA and ITTSB, and shown as relays IGWNA, ESWR and IQWNB for the crossover including track switches IQTSA and NTSB. The switch control relays IGWR and IiWN are shown for the track switch STS; and the relays ISWN and ISWR are shown for the track switch ISTS.

Each group of' switch controlling relays WNA, WR and WNB (or WN and WR) have associated therewith the necessary apparatus for controlling their track switches as typically shown in Figs. 1 and 2. These switch control relays also include contacts for the control of the illuminated track diagram indicato-rs as typically shown in connectio-n with Figs. l and 2, all of which has been omitted for the sake of simplicity. Also, each group of switch control -relays has associated therewith an emergency switch control lever SML, but only the -emergency switch control levers iSML and iBSML have been shown in detail, as their associated track switches `|STS and ESTS are the only ones in Fig. 3 which have what has been termed as derail protection control provided vin connection therewith, while the remaining groups of switch control relays have their emergency switch control levers associated therewith the same as described in connection with Fig. l.

The switch control relays WNA, WR and WNB (or WN and WR) have contacts for selecting the stick circuits -ior the eXit relays XR as typically taught in Fig. 1.

Fig. 3 has been entirely limited to the features which differ lfrom Figs. l and 2, rather than complicating it with `all the details which would Vnecessarily be duplicated from Figs. l and 2.

The arrangement-of Fig. 3 'is `more particularly directed to the manner -in which the entranceexit control provides for selectively energizing the switch control relays `in an interlocking group having acomplex track layout. This feature is accomplished in accordance with Fig. 3 by what has been termed a self-selecting route network based 'upon the series circuit principle that is, Whenthe opposite ends o'i a route circuitare energized, all of' the switch controlling relays'in that circuit are energized in series and the picking up of 'the switch controlling relays in such circuit effectively prevent the picking up of switch controlling relays for setting up conflicting routes.

For example, let us consider that the operator is desirous of clearing a route from the ysignal tov` the signal 1B; To do this, he operates the entrancebutton which energizes the `entrance relay ITINR, and then actuates the exit button which energizes the exit relay I'BXR. This closes an energizing circuit from through a circuit including front contact |'6llof relay HNR, back contact `|.6| of relay l'tXR, hack contact |62 of relay "|1WR,1lowerWinding of relay I'IWNA, back contact 1631er relay lBWR, lower winding of relay:|6WN,1back Contact v|61! of relay ISWR, lower Winding Yof relay |.9WNA, Tfront' contact |35 of relay l SKR, to The `current-which iiows'in this-'circuit causes the relays -l1WNA, |6WN and HWNA to pick 11p and operate their respective trackcswitchesto. corresponding normal positions. The picking up of relays IIWNA, HWVN and :13H/TNA completessa stick circuit for the exit relay MXR. :in a mannenanalogousto the stick circuit for relay v4XR for `example. After the track switches are operated into correspondence with theh'rcontrols, a. signal clearing circuit for signal 1:1 iscompleted upon the. same basicfprin'cples as described Iin--connection rwith Figs. 1 and 2.

the. `cleared condition of the route from tire-signal f|| to the signal y.13, a conflicting route cannot be established. For example, if the entrance relay .MNR 4were picked up to put-negative potential on the wire |1666, the relay I'SWR Acannot be .picked 'up becausecof the open conditiunol hack .contactl161 of relay ISWNA. Similarilyytho other branchfcircuit extending, from the .wire .F65 cannotfenergize the relay IWVR by .reason offopeniback contact ifil of relay HWNA.

This arrangement of Fig. 3 'provides the same Ieaturesof control andi` indication as pointed out in connection Ywith fliigs.` l and 2. As above mentioned a; route is'whqlly dependent upon its governing entrance button NB, so that in this parexample the vreturn .of entrance button 121MB (notshown.) to a normal position restores the signal to afstop indicating condition` .Wthlaself-iselecting:network of this character, there-are certainmoutecircuts in the interlocked group whichdo` not includeas many switch conimolrelays as do others. in the samegroup, so that :in such cases .it is necessary to provide balarming: resistors .in thesronte circuits having the smaller number Aof switch control relays. For example, thel route between the signals illA and 13 includes only two track. switches `while the route Lbetween `the signals il and |3 includes threeswiftches. Thus, the route circuit in the seit-selecting network corresponding` to the route between A:signals lll and |3 is compensated by the provision; oftheresistor |1s0. To'be more specic, and considering the :actuation of the entrance relay HNR' .andthe exit relay IUXR, a route circuit closed'rom. (-1-), `through a circuit infclu'ding front. contact |1| `of relay MXR, 4compensating resistor |10, lower winding of ,relay backcontact |12 of relay AI-(SWN, back contact i164 of relay IBWR, lower windingof relay HW'NA, back contact |65 of relay ISXR, front contact |13 of relay |3NR, to The energy which iiows in this circuit of course energizes the relays |6WR and |9WNA in series causing their `respective switches to `operate to corresponding reverse and normal positions and accomplishes the yclearing of the signal |3 in the usual way, as-described in connection with Figs. 1 and 2.

Optional routes-This track layout provides what has been conveniently termed optional routes, that is, two or more routes between two particular points. The system of the present invention is arranged to automatically determine the superiority between such routes, that is, the particular one of the optional (or parallel) routes that :shall be selected as the preferred route at any one time.

In this particular track layout there is one `routefibetween the 4signals |'4 and over the track switches 'iQTSA and IQTSB in reverse lpositions, andanother route over the track switches Vl ITSiA and I 1TSB in reverse positions. The selfselecting network has been arranged so as to give the superiority to the route over the track switches |9TSA and |'9TSB in reverse positions .whenthere is Ano conflicting route.

For example, 'let us assume that the operator rst actuates the entrance button ||NB (not shown) energizing'the relay HNR, and then ac- .tuates'theexi't button MXR (not shown) energzingithe relay |`4XR. Two route `circuits are thereby momentarily established.

`The .ii-rst route circuit is closed from through a circuit including front contact of relay HNR, back contact |6| of' relay IIXR, back contact |62 of relay |1WR, lower winding of relay HWNA, back contact .163 of relay ISWR, lower windingof relay |6WN, back contact |14 of relay I'SWNB, lower winding of relay IQWR', back contact |61 ofrelay IQWNA, wire |66, front contact l|15 of relay MXR, to

The second route circuit is closed from (-1-), through a circuit including front contact |60 of vrelayl INR, back Contact |6| of relay ||XRback contact |16 of relay |'1-WNB, lower winding of relay |1WR, back contact |68 of relay |1WNA, lowerfwinding of relay |8WN, back contact |11 .of relay `IBWR, lower winding of relay ISWNB, `back contact |18 of relay ISWR, wire |66, front IContact |15 of relay MXR, to

Both `of these circuits are energized simultaneously, but the relays |1WR, `|8WN, and ISWNB arel made slow acting, while the relays |1WNA, |6WN and IBWR are relatively quick acting and .thereforepick up immediately. As soon as the rela-yV |29WR picks up, `which is before the relay `|9WNB, for example, the open back contact |18 deenergizes the second route circuit. Therefore, the ,-rst route circuit is given the preference or superiority.

However, it may happen that a route isset up between the signal I3 and the signal' I6 causing the relays ISWNA and |6WR to be energized. Under such circumstances, the back contact |61 oi relay |9WNA is opened, so that only the second route circuit is energized. This causes the relays ISWNB, |3WN and |1WR to be picked up. Thus, an automatic selection between optional routes is provided by the system of the present invention.v

For onefreason or another, it might be desirable to--select the .second route over the track switches |1TSA and |1TSB in reverse positions even though the track switch ISTSA is 'not included in an established route. All that is necessary to do this is for the operator to actuate the emergency switch control lever I'ISML (not shown) to a reverse position which energizes the relay I'IWR. The picked up condition of the relay I'IW'R opens the back contact |62 in the route circuit for the first route and prevents the superior optional route from being automatically selected, and allows the relays I8WN and I9WNB to be energized in series with the lower winding of the relay HWR upon the actuation of the entrance and exit relays for the signals II and I4.

Derail protection- When a route is set up over the track switches I'ITSA and IITSB in reverse positions including the track switch I 8TS in either a normal or a reverse position, means is provided in accordance with the present invention to give derail protection to this route by operating the track switch IETS to a reverse position. In other words, when a route isv automatically set up between the signals' II and I5, or when a route is set up between the signals II and I4 by reason of the manual operation of the emergency switch lever IISlVLL (not shown), means is provided which operates the track switch IGTS to its reverse position so that any train which might overrun the signal I3, will be shunted on to the turnout track. This is accomplished by suitable circuit selections closing a circuit for the relay IGWR from. through a circuit including the upper windings of relay ISWR, back contact |80 of relay IBWN, front contact IBI of relay IIWR, to Such control of the track switch IETS by the derail protecting means, does not prevent that track switch from being employed in a route which is not conflicting with the established route'. In other words, when a route is set up over the track switches IITSA and I'ITSB in reverse positions, a route may be set up between the signals Ill and I3, or between the signals I and I4 with the track switch IBTS in a reverse position.

Similar control is provided for the track switch I8TS by reason of front contact -I82 of relay ISWR. which is effective to energize the relay IBWR when a route is established over the track switch ISTSA and ISTSB in reverse positions. The track layout of Fig. 3 only has these two possible examples of derail protection, but it is to be understood that any track layout to which the present invention is applied may have this derail protection applied at'all possible situations, by merely causing the route to be protected`to energize the proper switch control relay for the protecting switch through its individual manual emergency switch control winding. The individual manual control winding for the switch control relays is employed in connection with this feature so that the derail protecting circuits will not become involved in the usual route selections.

Having thus described an electric interlocking system for railroads, as one specic embodiment of the present invention, it is to be understood that various modiiications, adaptations, and a1- terations may be applied to meet the requirements of practice without in any manner departing from the spirit or scope of the invention except as limited by the appended claims.

What I claim is:

1. In a centralized tra'ic controlling system for railroads, a track layout containing a plurality of routes formed by track switches, circuit controllers for the ends of said routes, wires connecting said circuit controllers in a manner corresponding to said track layout, whereby there is a continuous route circuit for each route through the track layout, relays included in certain of said wires so that there is a relay in each route circuit corresponding to the trailing point position for each track switch in the route for that route circuit, whereby the closure of a circuit controller at each of the opposite ends of a route circuit energizes a relay for each track switch in the corresponding route which relay is representative of the proper position for that track switch in such route, contacts on each of said relays for opening, when that relay is energized, the route circuits for those routes, which conict with the route corresponding to said energized route circuit that are possible when the track switch for that relay is in an opposite position, and other means for individually energizing each of said relays.

2. In an interlocking system for railroads, a. track layout containing a plurality of routes formed by track switches, circuit controllers for the ends of said routes, wires connecting said circuit controllers in a network symmetrically arranged to correspond with said track layout, whereby there is a continuous route circuit for each route through the track layout, normal and reverse switch control relays for each oi said track switches except in the case of a crossover where a single reverse relay is common to both track switches of the crossover, said relays being included in the respective branches of said network corresponding to the trailing positions of the track switches which such relays represent, whereby the closure of a circuit controller at each of the opposite ends of a route circuit energizes the proper normal or reverse relay for each track switch necessary to establish the corresponding route, and back contacts on each of said normal and reverse switch control relays for opening said route circuits in which the opposite reverse or normal switch control relay is included, and manually operable means for individually energizing each of said switch control relays, said means being effective to energize only the normal or the reverse control relay for each switch at any one time.

3. In an interlocking system for railroads, a track layout containing a plurality of routes formed by track switches, ,circuit controllers for the ends of said routes, wires connecting said circuit controllers in a network symmetrically arranged to correspond with said track layout, whereby there is a continuous route circuit for each route through the track layout, normal and reverse switch control relays for each of said track switches except in the case of a crossover where a single reverse relay is common to both track switches of the crossover, said relays being included in the respective branches of said network corresponding to the trailing positions of the track switches which such relays represent, whereby the closure of a circuit controller at each of the opposite ends of a route circuit energizes the proper normal or reverse relay for each track switch necessary to establish the corresponding route, back contacts on each of said normal and reverse switch control relays for opening said route circuits for those routes which conict with the route corresponding to said energized route, switch machines for respectively operating said track switches, Vcircuit means associated with each said switch machine and controlled by the respective normal and reverse switch control relays for that track switch for causing its normal-:and reverse operation, a locking relay for each ytrack switch for preventing the response of its switch machine to its said switch control relays when such locking relay is deenergized, a pick up circuit for each locking relay including back contacts of its said normal and reverse switch control relays, and a. stick circuit foreach said locking relays including a front contact-of such locking relay and contacts lwhich complete such stick circuit only while said normal and reverse switch control relays yfor the corresponding track switch are out of `ycorrespondence with such track switch.

I4. In an interlocking system for railroads, a track layout containing `a plurality of routes formed by track switches, a stay-where-put entrance button for the entrance end of each router, a self-restoring exit button for the exit end of each route, an exitv relay for each exit button having a pick upcircuit .controlled .by such exit button, a circuit network symmetrically arranged to :correspond with said track layout, whereby there is -axcontimmus route circuit foreach route through the track layout, normal and `reverse switch control relays for each of said `track switches exceptin the case of a. crossover vwhere a single reverse relay is. common to both track switches ofthe cross-over, .said"relays 'being in- .cluded `in the respective branches 'of said network corresponding to the trailing positions of the track switches which such relays represent, entrancefcontacts. on each `of said entrance buttons and .exit contacts: on .each of said exit relays, means effective upon the actuation of only an entrance button .at one end ofa `route and the exit button at ,the opposite end of that route to close an entrance contact andan exit contact for energizing the ycorresponding routev circuit so that the proper normal orreverse relay foreach track switch is picked `up to establish the corresponding route, front contacts on said ynormal and reverse-switch control relays for completing a circuit corresponding .to said route, whichI circuit is wholly dependent -ior energize-tion upon the saidentrance button "forthat route and which circuit maintains energized the exit relay for such route, .and back contacts `on each of said normal and reverse switch control relays for opening the circuit bran-ches for the switch control relay requiring the opposite position of the track switch, whereby conflicting route circuits ,cannot be energized.

5. In an interlocking system -for railroads, a plurality of railway tracks interconnected by 4switches to form a plurality of routes, normal and reverse control relays for each of said switches, a plurality of interconnected route circuits for .said plurality of routes each of said route circuits including in series the normal or the reverse controlrelay for each switch in the :corresponding route, route control means including manually controlled means and asource of `current for energizing a route circuit and the control relays included therein, means controlled by the normal and the reverse control relays for each switch for operating the corresponding switch to normal and reverse positions respectively, and other manually controlled means for individually energizing either the normal or the reverse control relay for each track switch only if the opposite normal or reverse control relay is deenergized, whereby the route control and the individual control is eilectively interlocked.

`-6. IIn an interlocking system `for railroads, `a plural-ity of railway tracks `interconnected by switches tol form a plurality of routes, a normal and -a reverse control relay vfor each of said switches, a manually operable contactor means vfor each route end, an exit relay 'for each route end, a plurality of route `circuits one-for each of said routes and each of whichincludes in series the normalV or the reverse control relay for each switch in :the corresponding route and also a contact controlled by the manually operable contactor means for the entrance end of the route aswell asra `front :contacter the exit relay'for the exit vendl ofthe-routefor the direction oftrafne 4movement with which the circuit is fthen fassociated :and also 1a source of current for operating .the `control relays in the circuit, means controlled 4by the normal and the reverse control Lrelays lfor each switch for operating the corresponding switch Ato normal and reverse positions respectively, 'a :pick up circuit for each exit relay controlled by said manually operable contactor means for the corresponding route end, 'and a .circuit for each exit. relay separate from said route .circuits and .selectively made Vup rby said` normal and reverse control relays of the then energized route circuit and dependent upon the manually operable contactor means.. for the entrance end .of the corresponding route for :the direction of traflic with Awhich the route .circuit is .then associated.

7. In an .interlocking .system :for railroads, a plurality 4of railway tracks interconnected by switches `to form a plurality of routes, a .normal and a reverse control relay .for each of said switches, amanually :operable contact Lmeans for `each route end, an exit relay or each routev end, aplurality of route circuits ,one for each of said routes and each of which vincludes in series the normal or the `reverse control .relay for each switch in the corresponding route .and also a contact `controlled by the manually operable contact means for the entrance end of the route as well as a front contact of the exit relay for the exit end of the rout-e for the direction of trahie movement with which the. circuit is then associated andA also a `source of current for operating the relays .of the circuit, means controlled by the .normal and the reverse control rela-ys for each switch for operating the corresponding switchto normal and reverse positions respectively, a pick up circuit Vfor each exit relay controlled by said -manually operable contact `mea-ns for the corresponding route end, a stick circuit 'for' each `exit relay separate from said route circuits and `selectively made up by front contacts, rof saidn-ormal and reverse control relays of the then energized route circuit and dependent upon the manually operable contact means' for the entrance end of the corresponding route for the direction of tratc with which the lroute circuit is then associated, whereby an exit relayzisl not stuck up until after theresponse .of all. normal and reverse control relays for the 'switches in the particular .route to be set up; asignal 'for each route end, and means controlled `by said exit yrelays and said manually operable Contact means for the `route endsxfor operating said signals.

8. In an interlocking system for railroads, a plurality of railway Atracks interconnected by switches to 4form a plurality of routes, a staywhere-put entrance button for each route end, `a self-restoring exit` buttonv for `each route end', an entrance relay foreach route end, an exit relay for each route end, a control circuit'for each entrance relay energized with the entrance button for itsroute end in an operated position and including a back contact of the exit relay for that route enda pick up circuit for each exit relay energized with lthe exit button for its route end in an operated position and including a back contact of the entrance relay for that route end, normal and reverse switch control relays for each of said switches, a self-selecting circuit network including said normal and reverse control relays rendered eiective to energize the proper normal and/or reverse control relays to establish a particular route when only the entrance relay for one end of that route and the exit relay for the opposite end of that route are both picked up, and a stick circuit for each of said exit relays selected by front contacts of the appropriate switch control relays to include a front contact of the entrance relay of the particular route with which that exit relay is then associated.

' 9. In an interlocking system for railroads, a plurality of railway tracks interconnected by switches to form a plurality of routes, a staywhere-put entrance button for each route end, a self-restoring exit button for each route end, an entrance relay for each route end, an exit relay foreach route end, a control circuit for each entrance relay energized with the entrance button for its route end in an operated position and including a back contact of the exit relay for that route end, a pick up circuit for each exit relay energized with the exit button for its route end in an operated position and including a back contact of the entrance relay for that route end, normal and reverse switch control relays for each of said switches, a self-selecting circuit network including a plurality of interconnected route circuits for said plurality of routes each of said circuits including the control windingvof either a normal or the reverse control relay for each track switch in the corresponding route and also a back contact of the opposite control relay for each track switch in a corresponding route, means including said entrance and eXit relays for energizing each particular route circuit of said self-selecting network in response to the operation of only the entrance button for the entrance point to the particular corresponding route and the exit button for the exit point to the corresponding particular route, means controlled by said normal and reverse relays for each switch for operating the corresponding switch to normal and reverse positions respectively, and a stick circuit for each of said exit relays selected by front contacts of the appropriate switch control relays to include a front contact of the entrance relay of the particular route with which that exit relay is then associated.

10. In an interlocking system for railroads, a plurality of railway tracks interconnected by switches .to form a plurality of routes, manually operable contact means for each route end, an entrance relay for each route end, an exit relay for each route end, a circuit for each entrance relay controlled by said manually operable contact means for its route end and including a b-ack contact of the exit relay for that route end, a pick up circuit for each exit relay controlled by said manually operable contact means for its route end and including a back contact of the entrance relay for that route end, normal and reverse switch control relays for each of said switches for controlling that switch to its normal and reverse'positions respectively, a self-selecting circuit network including said normal and reverse control relays rendered effective to automatically energize the proper normal or reverse control relay for each track switch in a particular route to establish that route when the entrance relay for one end of that route and the exit relay for the opposite end of that route are both picked up, and a stick circuit for each of said exit relays separate from said self-selecting network and selectively made up by the control relays of the route with which that exit relay is then associated so as to include a front contact of the entrance relay for that route, whereby said control relays for that route and said exit relay for that route are all dependent for continued energization of the entrance relay for that route.

11. In an interlocking system for railroads, a plurality of railway tracks interconnected by switches to form a plurality of routes, manually operable contact means for each route end, an entrance relay for each route end, an exit relay for each route end, a circuit for each entrance relay controlled by said manually operable contact means for its route end and including a back contact of the exit relay for that route end, a pick up circuit for each exit relay controlled by said manually operable contact means for its route end and including a back contact of the entrance relay for that route end, normal and reverse switch control relays for each of said switches for controlling that switch to its normal and reverse positions respectively, a selfselecting circuit network including said normal and reverse control relays rendered effective to automatically energize the proper normal or reverse control relay for each track switch in a particular route to establish that route when only the entrance relay for one end of that route and the exit relay for the opposite end of that route are both picked up, a stick circuit for each of said exit relays selected by front contacts of the appropriate switch control relays to include a iront contact of the entrance relay of the particular route with which that exit relay is then associated, a signal at each route end for governing the entrance of traiilc into the routes emanating from that point, and means controlled by said entrance and eXit relays for operating said signals.

12. In an interlocking system for railroads, a plurality of railway tracks interconnected by switches to form a plurality of routes, manually operable contact means for each route end, an entrance relay for each route end, an exit relay for each route end, a circuit for each entrance relay controlled by said manually operable contact means for its route end and including a back contact of the exit relay for that route end, a pick up circuit for each exit relay controlled by said manually operable contact means for its route end and including a back contact of the entrance relay for that route end, normal and reverse switch control relays for each of said switches for controlling that switch to its normal and reverse positions respectively, a self-selecting circuit network including said normal and reverse control relays rendered eiective to automatically energize the proper normal or reverse control relay for each track switch in a particular route to establish thatl route when the entrance relay for one end of that route and the exit relay for the opposite end of that route are accroc? both picked. up, a normal anda reversal-correspondence relay for? each switch respectively picked up only when said normal and reverse control relaysl forv that switch arev energized incorrespondence with such switch, a lock relayfor each switch for preventing operation of thatk switch when deenergized,` an energizing circuit for each lock relay including trafc controlled contacts,- backl contacts of said normal and reverse correspondence relays for its switch; and

back contacts of said normal and reverse controlrelays for its switch, with a'front contact onsnch lockY relay for shunting. out.- said back contacts onsaid' control relays when suchf lock relay is' picked up, whereby each of said track. switches is'l'ocked yas soon as it assumes a proper position for! the route in which it is then. included asI indicated by the energization of its correspondence relays.

13. In an interlocking' system for railroads, a plurality ofv 4railway tracks interconnectedby.' switches to form a plurality of' routes, manually operable contact means for each route end, anentrance relay for each route end, an exit relay for each route end, a circuit for each entrance relay controlled'by said manually operable:v con-- tact-Y means for its routev end andi including al back contact of the exit relay for that route end, apickv up circuit for each exit! relay controlled' by said manually operable contact' means for its route end and includingv a back contact ofv the entrance relay for that route end, normal and reverse switch control relays for each of said switches for controlling that switch to its normal and reverse positions respectively, a seltselecting circuit network including said normal andy reverse control relays rendered-'effective to automatically energize ithe proper nor-mal` or reverse control relay for each track switch in a particular rou-te to-establish thats route when the entrance relay for one end of thatl route and the exit relay for thev opposite end oithat route areboth-picked up, a normal and a reverse cor'- respondence relay for each switch respectively picked up only when said normal and reverse L control relays for that switch are energized in correspondence with such switch, aI lock relay for each switch for preventingoperation o'fthat switch 'when deenergized, an energizing circuit foreach lock relay including trafhc controlled contacts, back contacts of said normal and reverse correspondence relays for its switch-back Contact off said normal and reverse control relays for its switch, with a iront contact on such lock relay for shunting out said back contacts` -on said control relays when such lock relay is picked up, whereby each of said track switches ifs locked as soon as it' assumes aproper position for the routeV in which it is then included as indicated by the energization of its correspondence relays, a signal at each-route end; control circuits for each signal including a front contact of said entrance relay atthat end, a back contact of each lock relay of the several'switches in the then-established route; and a front contact ci the exit relay for that route.Y

14; In a centralized trac controlling system for railroads; a power operated track'switeh; a signal for governing traiiic over said track switch; a traine condition relay controlled by tramo conditions adjacent said track switch; switchl relay means for controlling the normal and reverse operation-of said't-rack switch when selectively energized and rendered effective; 'nor-V mal vand reverse correspondence relays; anormal circuit for energizing said normal correspondence relay only when .said switch relay means is selectivelyl energized. tol cause a normal opera tion' of: said: track switch and said. track .switch` is. in; correspondence therewith; `aireverse cir cuit. for energizingv said reverse" correspondence relay only when: said-.switch relay .means is selec-'- tively energized to cause-al reverse operation. of! safidftrack` switch; and. said track switch is in correspondence therewith; signal control circuit' means for: at times clearing said; signal when rendered effective, said signal circuit means.y being selected by front contacts of. said correspondence relays-a, locktrelay for rendering said .f switch' relay means effective when picked up" and' ior renderingfsaidisignal circuit; means eiective when dropped away;. a. pick-up.` circuit. for.` saidV lock. relay including back contacts of saidl switch relay means .and airont contact of said tra-flic relay; and stickv circuit means for said lock-relay includingback contacts--of-,said correspondence relays and. a: frontv contact of. saidtrailic relay.-

l5. In an interlocking. system forrailroads;.-a;

`plurality of railway tracks interconnected' 'by power operated track-switchsto formac plurality of routes; normal andi reverse con-troll relays for. each ofsaid switches; manually-operable contact means-for the ends-loi. saidlroutes; a-routeestablishing circuit network having route lcircuits corresponding to said? routes and each route circuit energizing those of said normal' and-reverse control relays required to'- be energized-to Aset .up-the corresponding route-.said circuit network.` including contacts of saidcontrol relays in a manner effective-to' isolate eachv energized route circuit from all conflicting "routecircuits, and -eachparticular `rou-te circuit-of' said circuit network-being energized inA response to the operation of said manually operable contactmeans for the-opposite ends-1 of! the corresponding route; and circuit, meanscontrolled by' certain -o said normal and reverse control relays, when suoli relays are energized by a route circuit,` for energizing a particular normal or reverse control relayfor a particular conflicting route solas to operate the cor'- responding trackv switch to a-position toi give'derail protection to the-established route.

16. In an interlocking system for railroads; a plurality of railway tracks interconnected by switches to :form a plurality of routes; normal and reverse control relaysfor each of said switches; manually operable contact means for the ends o-f said routes;V a route-establishing cir#- cuit network having route vcircuits corresponding to said'rou-tes and each route circuit energizing those of said normal andf reverse control relays required to 'beenergized t'oset up the cor-respond'- ing ro-ute, said circuitV network including contacts of said? control relays in a-manner eiectiveto isolate each-energized route circuit from` all conflicting rou-te circuits, and eaclilparticularroute circuit ofsaidcircuit' networkf being -energ-ized in response totheoperation of-said manually operable contact means for the oppositev ends of' the corresponding" route; normaland reverseindicator lamps for each-of-v said track switches; and circuit means for energizing each ot said-indi` catcrv lamps whenever! theA corresponding normal or reverse control relay-'rorthat-switchis-energized independentlyof the position-1 of the switch.

17. In an interlockihgsys'tem-for railroads; 'a plurality of railway tracks int'eiazon'nectedV byswitches-to form{apluralityof'routesj a-miniatu're track! diagramforming var'plica oi said track layout; manually operable control means for the ends of said routes; normal and reverse control relays `for each of said track switches; a route establishing circuitnetwork having route circuits corresponding .torsaid routes, each route circuit beinglcapable, when energized, of energizing those of said normal and reverse control relays required to .be energized to set up the corresponding route, said circuit .network including contacts of said control relays in a manner effective to isolate each energized 'route circuit from all conflicting route circuits, and each particular route circuit of said 'circuit network being energized in response'to the joint operation of said manually operable contact means for the opposite ends of the corresponding route; means including indicator.v lamps for eachV position of each track switch forilluminating linear portions of said trackrdiagram so as to indicate the route set up when illuminated; and circuit means for each indicator lamp controlled by its corresponding normal or reverse control relay so as to be illuminated whenever such control relay is picked up and independently of the position of the corresponding switch. Y

18. In an interlocking system for railroads; a plurality of railway tracks interconnected by switches to form a plurality of routes; a miniature track diagram forming a replica of said track layout; manually operable control means for the ends of said routes; normal and reverse control relays for each of said track switches; a route establishing circuit network having route circuits corresponding to said routes, each said route circuit being capable, when energized, of energizing those of said normal and reverse control relays required tor be energized to set up the corresponding route, said circuit network including contacts of said control'relays in a manner effective to isolate each energized route` circuit from al'L conflicting route-circuits, and each particular route circuit of said circuit networkbeing energizedin response to the joint operat-ionv of said manually operable contact means for V the opposite ends of the corresponding route; indicator lamps for each position of each track switchso located on said trackv diagram, as Vto indicate the route ,set up when illuminated; circuit means for* eachindicator lampv controlled by its/corresponding normal or reverse -controlj relayso as to be illuminated `whenever such control relay is picked up; and

other circuit means-for each of said indicators for maintaining such Y rindicators illuminated whenever a train is occupying the route in which such track switches have been included.

19.*In a switch and signal control system, a plurality of track portions interconnected by track switches to form aV plurality of routes through artrack layout between signal locations, a circuit network including circuit portions corresponding ,to sai-d track portions and connected to conform to theroutes through Said track Vlayout, normal andreverse controlrelays for each of said track switches for governing the normal and reversey operation of the corresponding track switches; manually operable control-means Vfor each of said` signal/locations, means d including said circuit network effective in response to the operation of the manually operable control means foranjentrance point and the operation of the manually controlled means for an exit point to energize` those of said normal and reverse control relays required to set up a route between-said entrance and exit points, *contactsV oi" said normal andreverse control` relays includedin saidcircuit network and effective when the control relays for the track switches of a particular route are energized to 'set up that route :to isolate the circuit portions of saidnetwork correspondingvto that particular route from the circuit portions of other routes, circuit means controlled by certain ones of said normal andreverse control relays of said particular normal `or reverse route for energizing particular control relays for switches in routes conflicting with said particular route so as to operate the track switches corresponding to said particular control relays to positions to give diverging route protection forV said particular route which is then set up, and circuit means for clearing a signal at the entrance end of said particular route dependent upon the continued energization of said circuit portions corresponding to said particular route.

20. In a switch control system for railroads, a plurality of railway tracks interconnected by power-operated track switches to form a plurality of routes, normal and reverse control relays for each of said switches, manually operable contact lmeans for the ends of said routes, route establishing circuit means effective in response to the joint operation of the manually operable contact means for the opposite ends of a particular route to energize the normal or reverse control relays for the track switches in that particular route so as to set up the corresponding route, and circuit means controlled by certain of said normal and reverse control relays, when energized for said particular route, for energizing control relays for certain track switches in routes conflicting with said particular route so as to operate such track switches to positions oppositerto the positions required to set up such conflicting routes to thereby prevent trains from travelling over such conflicting routes into track switches included in said particular route.

21. In a switchicontrolsystem for railroads; a plurality of railway tracks interconnected by power-operated track switches to form a pluralit" ofl routes; normal and reverse control relays'forleach of said switches; manually operable contact means for the ends of said routes; route establishing circuit means effective in response to the joint operation of the manually operable contact means for the opposite ends'of a particular route to energize the normal or reverse control relays for the tracklswitches in that particular route so as to set up the corresponding route; circuit means controlled by certain of said normal and reverse control relays, when energized for said particular route, for energizing control relays for certain track switches in routes conicting with said particular route so as to loperate such track switches to positions opposite to the positions `required to set up such conilicting routes to thereby prevent trains from travelling over such conflicting routes into track switches included in said particular route; a. normally inactive auxiliary lever for each of said track switches, said levers having normal and reverse operated positions; and circuit means associated with each lever for energizing its normal or reverse control relay when suchvlev'er is actuated to a corresponding'norrnal or reverse position only provided the opposite normal or reverse control-is deenergized, whereby the operation of an auxiliary lever for a 'track switch cannot interrupt or change the normal or reverse relay in a route set up by said route establishing means. `j l l 22.-In a switch and signal control system for railroads; a power-operated track'Y switch `including in a detector track .sectionyan signal for governingV tramo over said. track switch; a nor-v mally energized track, relay deenergized whenever said` detector track section isoccupied by a spondence. relayl only when said switch control' relay means is selectively energized to cause the normal operation of said trackswitch and said track. switch is in correspondence therewith; aj

reverse circuit for; energizing said reverse correspondence relayl only when said switch control4 relay means is selectively energized to cause a reverse operation of said track switch and said track switch? is in correspondence therewith; a. pick-up circuit for said-lock relay 4including back contacts of.-.sa id switch controllrelay means,

a front contact ofsaid track relay, and back contacts of said normal and reverse correspondence relays; stick circuit for said lock relay including a front contact of said-V lock relay, said backcontacts of saidl normal and reverse correspondence relays, and said front contact of said track relay, wherebyl the back contacts of said switch control relay means are excluded from the` control of said lock, relay when it is once picked up; and a circuit for clearing said signal, said. circuit being closed only when a particular one of said correspondence relays is picked up and said lock relay -isudropped away.

23. In an interlocking system for railroads;` a plurality of railway tracks interconnected by power-operated track switches to f form a plurality or routes, and said tracks being divided into track circuits; a miniature track diagram forminga replica.- ofiV said track layout; a manually operable contact means on said track diagram for the ends of said routes; .normal and reversecontrol relays for. each of said track switches for controlling its power operation; route establishing circuit means-eiectivein response `to the,

joint operation ofthe manually `operable contact means for only theopposite ends of aparticular route to energize-the normal or reverse controlv relays for `the track switches' in that particular route -soas to operatethe track switches topositions to set up such particular route; normal and reverse indicator lamps for' each position of each track-Switchs@ located on said track'v diagram as to` indicatev the position of each switch by the illumination of the corresponding.

normal or reverse indicator lamps; circuit means foreach indicator lamp controlled b-y its corresponding normal orreverse control relay so as to be illuminated when. such control relay is picked'up;` and other circuit means for each indicator lamp` controlled so as to be illuminated in accordance with the position of its track switch whenever the track circuit. in which its track switch is locatedis occupied by a train; whereby a route is visually indicated on said track diagram whenever it is set up or is. occupied by'a train.

24; In combination, a detector sectionof railway track including a two-position track switch, av track relay for said detector section, indication means controlled in accordance with the position' and lockedcondition ofthe trackswitch, a track:

diagram arranged to vvform. a miniature. representation of' said detector section, threedamps for illuminating the tracks of said diagram compris-- ing one for each branch track extending in the trailing direction from the switch and one for the single track extending in the facing direction from the switch, a circuit controlled only by av back contact of said track relay for lighting said single track lamp and a circuit controlled. by a back contact of said track relay and by said indication means for lighting one branch track lamp or the other in accordance with the position of the track switch.

25;.. In combination, a detector section of railway track including a two-position track switch, a track relay for said detector section, indication means controlled in accordance with the positiony and locked condition ofthe track switch, a track diagram arranged` to form a miniature representation of said detector section, a lamp for illuminating .each branchtrack of said diagram extending in a trailing direction from the representation of the, track switch, and a circuit controlled by `a. back contact of. said track relay and by said,` indication means for lighting one branch track lamp or-the other in accordance with the position of the track switch.

26. In an interlocking system for railroads,` a: track layout comprising a plurality of railroad tracks connectedk by power-operated track switches. to form a plurality of. routes` between signal locations, a control. panel having thereon a miniature track diagram of said track layout, manually operable contact means. located on said track diagramadjacent each signal location, a stick relay for eachV route end, a pick-up circuit. for each stick relay controlled by the manuallyY operable contact means for the corresponding route end, normal and reverse switch control relays for governingthe operation of theswitches.- to the corresponding normal or reverseposition; a route establishing circuit network comprising: a plurality of interconnected route circuits each corresponding to one of said routes and responding to the operation of said manually operable,-

contact means belonging tothe Signal locations: for the ends of a given route to energize the route stick circuit means. including contacts of saidA switch control. relays for maintaining the-Stick.. relay at theexit end of a given route energized;

until the corresponding route circuit is de-energized. t

27.,In a. switch and signal control systemior railroad track layouts having a plurality of tracks connected by power-operated:4 track.

switches movable to provide a plurality of routes; between signal locations, the combination witl'na` miniature track diagram of said tracklayout, a

manually operable devicelocated onsaidtrack diagram adjacent eachV signal represented there.- onand adapted` to be actuatedby. an operator to define the corresponding signal: location as the: entrance or exit end of a desired route, route:- establishing meansresponsive tothe joint. act`u-'- ation of the manually operabled'evicesfor the signal locations at the ends of.V any given router' for positioning the track switches in that route to the normal or reverse position as. required' and for controlling the clearing-of. a signal for! governing train.` movement, throughv that route, a. detector tracksectionA and. a; .track relay for. each switch, a. pluralitycifdirectional stick; re-

lays associated with each of said detector track sections and controlled'by their track relays, means effective when a route is set up by said route establishing means for operating one of said stickrelays for each of the detector track sections in that route, and Visual indicating means on said track diagram for illuminating substantially linear portions of track on said track diagram belonging to the normal and reverse positions of each of said switches when a directional stick relay for the corresponding detector track section is in its operated condition, whereby the illumination of portions of the track diagram to denne the position of the switches in an established route is maintained while a train is travelling through that route.

28. In an interlocking system, a track layout comprising, a plurality of track Sections interconnected by different switches to form different traic routes between signal locations, said track layout including two alternative routes/between the same signal locations one of which is preferred and the other of which is secondary, a miniature .track diagram of the track layout having a manually operable.contact for each route end, a normal and a reverse switch control relay for each switch governing the operation thereof to the normal or reverse position, a route vnetwork comprising, a plurality of interconnected routeV circuits each corresponding to one of said routes and each including in series the normal or the reverse switch control relay for each switch in theY corresponding route, means responsive to the jointoperation of the contacts for the opposite ends of a given route to energize the route circuit to pick up the switch control relays for that route, said means being normally effective in the case of saidalternative routes to energize the route circuit to .pick up the switch control relays for one preferred route only, said means being effective in case such preferred route is not available to cause energization of the route circuit to pickup the switch control relays for the secondary route only, and means controlled by each route circuit when energized to operate one or more of the track switches as required to establish thecorresponding route and also to control the clearing of a signal for train movement over that route.

29. In an interlocking system; a track layout comprising a plurality of track .sections interconnected by track switches to form different traiiic routes between signal locations, said track layout including at least two alternative routes between two of the signal locations, one of which alternative routes is preferred and the other of which is secondary; a control panel having a miniature track diagram of the track layout; manually operable contact means on said track diagram for each route end; a normal and a reverse switch control relay for each track switch except in the case of a crossover where a single reverse switch -control relay is `common to both of the .track switches of the crossover; a route establishing circuit networkcomprising a plurality of interconnected route circuits each route circuit corresponding to one of said routes, and each including in series the normal or the reverse switch control relay for each switch in the corresponding route; means responsive to the joint operation of the manually operable contact means for the opposite ends of a given route to energize the route circuit for that route to pick up the normal and reverse switch control relays in such route circuit, said' means being normally'effective in the'case of said 'alternative routes to energize the route circuits for both suchl routes but to pick up the switch control relays for the preferred route more quickly than the switch control relays for the secondary route can respond; contacts on said normal and reverse switch control relays included in said route establishing circuit network and eiecti've when the switch control relays for the track switches of a particular route are picked up to separate the circuit portions of said network corresponding to thatl particular route from all other route circuits and also prevent the energization of the route circuits'for conliicting routes; and circuit means controlled by the switch control relays for each track switch to operate that track switch to the normal or reverse position when the normal or reverse switch control relay is picked up, whereby the operation of manually operable contact means for the opposite ends of a particular route causes the establishment of that route and in the case of alternative routes causes the establishment of a predetermined one of such routes.

30; In a switch and signal control system; a

plurality of track portions interconnected byV track switches to form a plurality of routes between signal locations of atrack layout, said track layout including atleast two alternative routes between two of said signal locations; a route establishing circuit network including circuit portions corresponding to said track portions and connected to conform to the routes through said track layout; a normal and a reverse switch control relay for each of said trackl switches except in the case of a crossover where a single reverse switch control relay is common to the track switches for both ends of the crossover, said normal and reverse switch control relays for each switch being included in series in the route establishing circuit network in positions corresponding to trailing point'positions for its corresponding track switch, and in the case of alternative routes between two signal locations each normal and reverse switchlcontrol relay for a preferred one of such routes being slow acting upon its energization; contacts on said normal and reverse switch control relays included in said route establishing circuit network in such a manner as yto be effective, when the switch control relays for the track switches of a particular route are energized, to separate the circuit portions of said network corresponding to that particular route from all other circuit portions of said route establishing network, manually operable contact means for each signal location and effective upon its actuation to always apply a particular electrical potential to the circuit portion of said route` establishing network terminating for such signal location, said particular potentials being of opposite polarity for the opposite ends of said routes, whereby the actuation of a manually operable contact means for the entrance and Y exit ends of particular route energizes the normal and reverse switch control relays for all of the track switches in that route as required with such energization always having current flow in the same direction irrespective of the direction of trac to be established in the corresponding route, and whereby the normal and reverse control relays for a preferred route are effectively energized before the control relays of a secondary route and effect the opening of the circuit portions for such secondary route; and circuit means controlled by desistir* the switch control relays for each track switch tooperate that track switch to the normal or reverse position lcorresponding to the particular normal or reverse control relay picked up 31. In a system for controlling power operated cuit controllers for the ends of said routes, wires connecting said circuit controllers in a manner to form a circuit network corresponding to said track layout, switch control relays included in certain of said wires so that there is a switch control relay for each trailing position of each track switch in every available route through the track layout, means eii'ective upon the operation of said manually operable circuit controllers for route ends at the opposite ends of the track layout for applying opposite potentials to the wires extending to such circuit controllers to thereby energize the normal and reverse switch control relays for the switches of the route or routes between such route ends, a contact on each switch control relay for opening the circuit of the switch control relay for the opposite position of its track switch, means for rendering certaincf said switch -control relays slow in picking up so as to give a preference to a predetermined one of the route circuits for the alternative routes but allowing the switch control relays of the route circuit for the other route to become picked up if the preferred route is unavailable, an auxiliary winding on each of said switch control relays, and auxiliary circuit means for at times individually energizing said auxiliary windings of certain of said switch control relays.

32. In a switch control system for railroads; a track layout including a plurality of track switches to form a plurality of routes through the track layout, normal and reverse switch control relays for each of said track switches except in the case of a crossover where a single reverse yswitch control relay is common to the track switches for both ends of the crossover, circuit means controlled by the normal and reverse switch control relays for each switch for governing the power operation of that switch to the corresponding normal or reverse position in accordance with the particular switch control relay then energized, manually operable contact means for the ends of said routes, route establishing means elective in response to the joint operation of the manually operable contact means for the opposite ends of a particular route to energize the normal or reverse switch control relays for the track switches as required to set up that particular route, an auxiliary winding on each of said normal and reverse switch control relays, a normally inactive auxiliary switch control lever for each of said track switches and each of said levers having normal and reverse operated positions, and circuit means controlled by each lever for energizing its associated normal or reverse switch control relay when such lever is actuated to a corresponding normal or reverse operated position only provided the opposite normal or reverse switch control relay is deenergized, said means acting in the case of a crossover to energize the normal switch control relays for both of the track switches at the opposite end of such crossover, whereby the operation of an auxiliary switch control lever for a track switch cannot interrupt or change the normal or reverse control relay in a route set up by said route establishing means.

33. In an interlocking control system, a track layout comprising a plurality oi' track sections interconnected by track switches to form direrent tiaic routes, a track relay i'or each section, a miniature track diagram or said track layo-ut having linear portions representing the track sections, route control means :or each route erl'ective when energized to operate the track switches as required to establish such route, a directional stick relay for each direction Ior each track section, means enectlve when a route is iully established i'or releasing selected ones oi' said relays Ior one direction including one relay ior each section oi such route, an indication circuit means I'or each section controlled by back contacts of the two directional relays for such section, means controlled by said indication circuit means lor illuminating the corresponding section or' the representation or' the established route in the track diagram when either one oi said associated directional stick relays is deenergized, and means responsive to the movement or' a train over such route to reenergize the stick relays for the route.

34. In a switch and signal control system for track layouts comprising a plurality of track sections connected by one or more track switches to form dilerent traliic routes, a miniature track diagram of said track layout including linear portions adjacent the switches representing their normal and reverse positions, visual indicating means including lamps for illuminating said linear portions substantially throughout their length, switch control relays for governing the operation of the switches to normal and reverse positions, circuits controlled byy said switch control relays for lighting said lamps, manually operable buttons on said track diagram for designating entrance and exit ends of desired routes, route controlmeans responsive to the actuation of buttons to designate the entrance and exit ends of a route for energizing the appropriate switch control relays to cause operation of track switches to positions required for said route, switch position indicating contacts closed in accordance with the operated position of said switches, a section locking relay for each track section automatically de-energized when that track section is included in an established route and maintained de-energized until a train has been passed over said track section, and circuit means controlled by back contacts of said section locking relays and by said switch position indicating contacts for selectively lighting said lamps to illuminate linear portions of said track diagram included in an established route although said switch control relays are de-energized.

` 35. In an interlocking control system, a track layout comprising a plurality of track sections containing track switches adapted to be interconnected to form different tralic routes, a track relay for each section, a miniature track diagram of said track layout having linear portions representing the track sections, manually operable buttons on said track diagram for designated entrance and exit ends of desired routes, route control means for each route eiective when energized by actuation of buttons to designate entrance and exit ends of that route to operate the track switches as required to establish such route, a section locking relay for each direction for each track section, each effective when deenergized to prevent the operation of the track switch in such section, means eifective when a 

